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Thread: Can't get BIG cammed '17 Sierra to hot start worth poop...

  1. #1
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    Can't get BIG cammed '17 Sierra to hot start worth poop...

    17 Sierra, 5.3, some idiotically giant cam somebody else installed. The TSP "BD" cam or something...Trims are dialed in +/- 2%, dropped VT down to meet my commanded idle, etc. and with throttle help it'll start and settle in to idle just fine. Truck purrs great. But this thing *WILL NOT* start without help from the throttle pedal. What am I missing? Note, I am only having an issue with start ups. The rest of the trucks performance seems ok.

    Thanks
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  2. #2
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    You'll have to go to the Airflow tab, then click General, then find the Cranking Base Airflow table. Increase it by 30% in the 133-up temp area to start with. That'll get you in the ballpark. You may have to go even higher.

  3. #3
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    What he said, but to add to it, if that's honestly the torque model you're running, then it needs to be fixed in the idle areas too. It looks like torque isn't changing at all from one end to the other - torque in idle area will greatly effect how it starts and keeps running.
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

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  4. #4
    Senior Tuner SultanHassanMasTuning's Avatar
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    6_GettingThere_MAS.hpt

    give this a shot
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  5. #5
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    You guys are great, thank you!